MNRE Releases Draft Guidelines for Solar Inverter Series Testing Under 2025 Goods Order

The Ministry of New and Renewable Energy (MNRE) has introduced draft guidelines aimed at the series approval of solar photovoltaic (SPV) inverters for laboratory testing. This initiative is part of the implementation of the “Solar Systems, Devices, and Components Goods Order, 2025.” The guidelines are intended to assist testing laboratories and manufacturers in streamlining the approval process for various models of solar inverters under a unified series, particularly when there are changes in design or materials.

These guidelines pertain to SPV-based off-grid, grid-tied, and hybrid inverters. A product family is defined based on the maximum configuration of components and sub-assemblies, where all models share the same essential hardware and firmware. For safety and performance testing, the highest-rated model in a series will be tested according to standards IS 16221 (Part 2):2015 and IS 16169:2019, with a single report issued that covers all lower-rated models in the series. However, for standards such as IS/IEC 61683:1999 and IS 17980:2022 (IEC 62891:2020), each model must undergo individual testing due to potential variations in efficiency.

All inverters within a family must maintain the same input/output voltage, frequency, number of output phases, PCB layout, insulation class, control algorithm, and cabinet design. Any modifications in internal components, construction, or firmware that could impact safety will necessitate retesting. Each product model must feature a label that includes vital information such as the manufacturer’s name, model number, input/output ratings, and protection rating. If fuse ratings are specified, this information must be displayed near the fuse holder.

Manufacturers are required to submit various technical documents alongside their samples, including datasheets, single-line diagrams, PCB layouts, bill of materials (BOM) lists, firmware versions, and manuals. Testing laboratories must confirm receipt of all necessary documentation before commencing tests. If a sample has already been submitted or is in the submission process, manufacturers must provide an undertaking to comply with the new guidelines for BIS registration. In the event of a test failure, manufacturers may resubmit a new sample, and only the failed test sequence will be repeated after reviewing any changes in components and construction. However, only one failure is permitted per test sequence; any additional failures will lead to disqualification.

For safety tests, two samples of the maximum-rated model must be submitted, and tests must be conducted according to IS 16221 (Parts 1 and 2). Collaboration between laboratories and manufacturers is encouraged during critical tests to ensure proper setup and execution. The guidelines also stress the importance of maintaining the confidentiality of submitted documents by testing laboratories.

Furthermore, products manufactured at different locations must undergo separate testing. All brand names and model numbers must be included in the test reports, even if only the highest-rated model is physically tested. The guidelines are currently open for stakeholder feedback, which can be submitted within 15 days to the email addresses provided in the memorandum. Once finalized, these guidelines will become mandatory for all relevant products seeking BIS registration under the new solar goods order.